Telephone-receiver.



B. B. CRAFT &J. N. RBYNULDS.

TELEPHONE RECEIVER.

APPLICATION FILED JAN. 2, 1912.

1 Patented May 20, 1913.

/hVenfo//sx #m fy. d0 0n m .y am WN .Mm Z w UNlTED- STATES vPATENT OFFICE.

EDWEED E. CEAET, or EACKENSACK, NEW wEEsfEY, AND JOHN N. EEYNoLDs, oF GEEENWICH, CONNECTICUT, yAssIGNoEs 'ro WESTERN ELECTRIC COMPANY, 0E NEW YoEK, N. Y., A CoEPoEATIcN or ILLINOIS.

TELEPHONE-RECEIVER.

specification of Letters Patent. Application led January 2, 1912. Serial No. 668,829.

-United States, residing at Hackensack, inthe county of Bergen and State of New Jersey, and at Greenwich, in the county of Falrfield and State of Connecticutrespectively, have invent-ed a certain. new and useful I mprovement in Telephone-Receivers, of which l0 the following is a full, clear, concise, and exact descriptiom This inventionl relates to telephone' re- ,ceivers, more particularly to telephone receivers of the bipolar type in which the magnet coils are inclosed in acup, forming therewith al structure in which the relation of the parts is maintained constant. v l

An object of this invention is to provide a magnet system for a' telephone receiver, in

I 2,0 which t-he various elements are made of straight bar stock', electrically welded together, therebyeliminating the trouble due to warping when the magnet system is made -of stock bent to shape, and the tr'ouble due .25 to a plurality of joints when the, magnet system is composed of straight bar stock bolted or riveted together.

Y Another object of this invention is to provide a cup in combination with the magnet system, the cup acting as a spacing piece for the free ends of the magnet, the cup and the magnet being lheld together in such relation that the adjustment between the diaphragm and the ends ofthe magnet poles 1s maintained constant under allconditions o'f service. v In' the drawings-Figure 1 is a sectional view of a receiver, showing the parts' assembled, andthe means for clamping the 4,0 cup to the magnet system; Fig. 2 is a detail perspective view of the magnet system; Fig.

3 is a front view of 'the .inclosing cup. y Referring to the ii ures, the bar magnets the magnet system and 11 and 12 are made o straight bar stock and areelectrically welded tothe heel piece 13.A

Throughthe center-*of the heel piece 13 passes the threaded clamping bolt 14.-. A cu 17, of non-magnetic material, and pro- I l vi ed with rectangular slots through which the polepieces 1,5 and 16 pass, is securely clamped to the bar magnets 11 and 12 by the threaded clampingA bolt 14C. The pole 'piecesl and 16 are electrically welded to the bar'` magnets 11 and 12, and extend through the slots in the cup, said slots prop- Patented May 2o, 1era.

insuring the holding of the cup 17 and its attached magnets 11 and 12 centrally within the-casing 32. Upon the face of the flange 33 is an annular ring 18 to which is clamped the diaphragm 19. Thecup and its attachments are clamped in place by means of the earpiece-34 which is provided .with the annular ring35, said ring pressing upon the edge of thev diaphragm 19, thereby holding said diaphragmand cup 17 in place. Connectors 20, passing through perforations-in the cup, and clamped thereto by nuts 21, are provided for making connection with the coils 26. V l It will beseen that the magnets and their attached pole pieces and coils are supported within the shell or casing entirely rby the cup'17 that any changes 1n the dimensions of the cup due to changes in temperature,

whereby the distance between the ends of the pole pieces and the diaphragm might be changed, are compensated by an equal change in the length ofthe pole pieces, with the result that the air :gap between the diaphragm and the pole ieces is kept constant 1n length. Further, t e electric welding of the heel piece and thepole pieces to the mag- -nets renders the magnetic circuit complete,

the only break or high resistance point for the passage of the' magnetic flux being the air gap between the diaphragm and the pole pieces. The previous forms of magnetic paths of'- similar character lacked the etliciency of the presentI device, in that the riveting or clamping of the magnets, heelpiece and poleV pieces together did -not ive an unbroken metallic path such as is ov tained by this construction. j

1. In a magnet system for telephone receivers, a permanently 'magnetized steel bar `and a soft iron pole-piece'welded thereto.

2. In a magnet system for telephone receivers, a soft lron pole-piece and a hardened steel bar welded together \end toendn.

3. In a telephone receiver, in combination a magnet system comprising two straight bar sections, a heel piece .therefor welded thereto at one end, a cup having slots therein and abutting against the bar sections,pole pieces welded to the bar sections at the end remote from the heel piece and passing through the slots in the cup, and means passing Vthrough the heel piece' for clamping the cup to the bar sections.

4. Ina telephone receiver, 'the combination :of a magnet comprising bars and a heel piece welded together, a "cup, pole pieces welded to said bars' and extendingthrough perforations iii-said cup, non-magnetic clamping means for clamping said cup to said magnet'ars on said pole pieces, and a diaphragml clamped to said cup in position to be acted upon byA said pole pieces.

5. In a telephone receiver, in combination ajmagnet system comprising bars and a heel piece welded together, pole pieces for said bars welded thereto at the end remote from the` heel piece, a cup having' perfora-y tions itting over said pole pieces and abutting against the magnet bars, a threaded bolt passing through a perforation in the heel piece and through a threaded hole in the cup, whereby the cup is clamped to the magnet system and in fixed relation thereto.

6. A magnet system for a telephone receiver comprising a horseshoe magnet having its -heelfpiece and pole pieces welded thereto, of a spacing plate for the pole pieces comprising a cup having perforations spaced apart, a threaded perforation in said cup centrally located with respect to said pole pieces, a threaded bolt passing through .the heel piece and threading into said cup,

whereby `the cup is clamped in xed relation to the pole pieces.

In witness whereof, we hereunto subscribe our names this 29th day of Dec. A. D., 1911.

EDWARD B. CRAFT. JOI-IN N. REYNOLDS.- Witnesses:

IRVING MACDONALD,4 WJ F. HoFFMAN. 

